Summary of the Invention
The invention relates to a device for testing and reprocessing objects processed in a processing station. A conveying device moves several objects arranged in a line in pickups through the processing stations. A controllable feeding device, which carries the objects, leads the objects, one after another, individually to the conveying device. The objects are led appropriately away from the conveying device. A control stops the processing station in case that it detects an insufficiently processed object, at least for the duration of a processing cycle, and delivers again the insufficiently processed object by means of a conveying device to the processing station.
In a labelling device working according to this principle, the objects to be labelled, for example ampoules or other containers, are led over by an intake worm gear to a plate that rotates slowly around a vertical axis. The plate has on its peripheral edge, equidistantly spaced pickups for the ampoules and moves the ampoules held in the pickups in an intermittent movement during the processing cycle past a device that dispenses the labels. An optical testing device, spaced from the point of transfer of objects from the worm gear to the plate by several pickups, checks out the position and the presence of the labels. A discharge worm gear takes the labelled ampoules from the plate.
The ampoules are shifted by a discharge lever operating within the cycle time of the plate from the pick-ups of the plate into the intake path of the discharging worm gear. When the testing device finds a not labelled ampoule, the discharge lever is not activated while this ampoule moves along. The unlabelled ampoule remains on the plate and is led after a full rotation of the plate again into the label dispensing device. The intake worm gear is stopped while the unlabelled ampoule moves along.
Due to the intermittent movement of the plate, the ampoules are subjected to high acceleration forces. The plate is stopped for half of the time of each cycle time and moves during the other half. In spite of the high speed of movement of the ampoules, the working cycle frequency remains relatively low. The working cycle frequency is additionally limited by a discharge lever shoving off the ampoules radially to the plate. The discharge lever must, within the time of a working cycle, shove off an ampoule from its respective pick-up on the plate as well as get out of the path of movement of an unlabelled ampoule. At high working cycle frequencies, the discharge lever applies high acceleration forces to the ampoule.
It is the object of the invention to increase constructively the working cycle frequency of the device explained above. To accomplish this end, the conveying system moves the objects in a continual, uniform movement from the feeding device over the processing station to the conveying mechanism. The testing station examines the result of the processing for every object during the processing of this object in the processing station. The conveying direction of the conveying device is reversible by a control upon detecting an insufficiently processed object. The control stops first the feeding device, then the conveying mechanism until the insufficiently processed object has reached the processing station for reprocessing and reverses. The conveyor mechanism is reversed again and the feeding device immediately or thereafter operated.
Since the conveying system works continually, the rate of processing is not reduced by the intermittent acceleration and braking. Since the result of processing is available at the end of each processing operation, the feeding device can be stopped directly after the end of the processing operation. For braking the conveying device working at an especially high speed there is thus almost a complete processing cycle available. The conveying mechanism can thus be braked gradually. The return run of the conveying device guides the insufficiently processed object through the braking path back into the processing station. The conveying away mechanism can continue to work continually during the reprocessing phase. No separately controllable, mobile discharge levers or the like are necessary. The conveying device and the feeding device work preferably in straight lines. The feeding mechanism conveys expediently merely a few objects to be processed, so that it can be fast braked at the beginning of the reprocessing phase.
The aforementioned object is solved according to the invention in an alternative manner so that the conveying device moves the objects in a continual, uniform movement from the feeding device over the processing station to the conveying device. The direction of conveyance of the conveying device is reversible and the objects placed in the pick-ups of the conveyer device can be conveyed along the feeding device in a reverse direction at the point of feeding. The control stops the feeding device upon finding an insufficiently processed object and reverses the conveying device until the insufficiently processed object has at least reached the processing station and then reverses the conveyigg device and engages the feeding device.
In this device, the pick-ups of the conveying device move along transversely to the direction of movement of the feeding device where they are fed with the objects to be processed. Before reaching the feeding device, the pick-ups of the conveying device move through a "buffering area" in which the objects to be processed can move in along the feeding device after the reversal of the conveying device. This buffering area is suitable for designs in which the testing device of the processing result examines not at the location of the processing device but at a distance from it in tee direction of conveyance.
The continually moving conveyor device can also be gradually braked even in a device where, because of the buffering zone, eventually even more than one processing cycle can be practiced. Moreover, the feeding device can also be gradually stopped so that when braking, one or more objects to be processed are introduced in pickups to the conveying device, operated in a braked down operation. The feeding device is conveniently controlled so that, after determining an insufficiently processed object, the feeding device is braked down, while it brings the following object into the respective pickup of the conveyor device and is brought immediately after to a standstill.
In order to keep the time of the reverse movement of the conveying device during the return of the insufficiently processed object into the processing station as short as possible, the testing station checks the result of processing for each object, preferably during the processing of this object in the processing station, i.e., during its processing cycle.
In preferred embodiments, the conveying device and/or the feeding device is driven by an electric step motor, most appropriately by separate step motors. Such step motors are rotated by driving pulses always by one predetermined angle of rotation per pulse. By changing the pulse rate, it is possible to control the driving speed and eventually the acceleration and braking processes. By counting the pulses, it is possible to control exactly the distance over which the feeding device and the conveying devie move the objects. Instead of a step motor, it is also possible to use other electric motors, especially d.c. motors with a permanent magnet stator or a disc rotor motor which are connected preferably to a control circuit with a tachometer monitoring the actual r.p.m.
The processing station is preferably a labelling device for applying adhesive labels on objects fed by the conveying device, especially on containers, ampoules, syringes or similar. Other areas of application are for example washing, filling, closing or printing containers or similar.
In the following pages, examples of execution of the invention will be explained in detail based on the drawings.